Collapsible bags made from sheets of flexible thermal plastic are known for storing, shipping, and dispensing products such as disposable diapers, etc. Such bags preferably include a handle for carrying the product and an opening for providing access to the interior of the bag.
It is highly desirable that such bags assume a cubic or block shape when filled and used. In transit, such shapes can be stacked together compactly without unused, wasted space. On the store shelf, such shapes stack better and display their graphics better. After purchase, these shapes stand upright in the customer's closet or on the customer's shelf.
Achieving and tending to maintain a cubic or block shape is particularly difficult, however, with flexible thermal plastic sheeting, which does not tend to hold any solid shape. Thin flexible plastic sheeting has the desirable features of economy and ease of manufacture in high-speed, automatic machinery, but the thinness and flexibility, which make it desirable in those respects, prevent it from easily achieving and maintaining the desired cubic or block shape.
Handles are also a desirable feature on such bags. In the prior art, some handles, as a consequence of high-speed automatic manufacture, have extended around the entire perimeter of these bags, or have extended between their narrow ends. The use of such handles (for example, the handle disclosed in U.S. Pat. No. 4,550,439, "Plastic Bag with Carrying Handle," invented by H. R. Peppiatt and John S. Thomas) has tended to destroy the desired shape, particularly when the bag is partially empty. Because of lifting forces transmitted to the ends of such bags, they have a tendency to distort and yawn open when carried.
An additional complication in the use and manufacture of such bags is the recent trend toward compacting soft products, such as disposable diapers, before placing them in plastic bags for distribution. Compressing such products before inserting them into plastic carrying bags minimizes the space required by the plastic bag and its contents. Compressed products, however, may be more difficult to insert into the bag.
At present, however, plastic bags manufactured on high speed machinery in continuous processes may include tucks, folds and substantial overlapping of excess plastic. These tucks, etc. may make it difficult to insert product, particularly compressed product, and also may make the bag lumpy and unsightly for display purposes.
The present invention, however, provides a cubic or block shape for the bag and a handle which allows easy transportation of such a bag. Moreover, because the carrying loads are distributed essentially only along the front and back walls of the bag, the handle of the present invention tends to provide and maintain the cubic or block shape and to provide smooth sides, even when the bag is partially empty. The present invention also provides a mass production technique for fabricating such a bag.
In addition, the structure of the present invention provides good characteristics for pourability of granular, powder, or pelletized products.
A further problem solved by the present invention is that of providing smooth and easy access to the interior of such a bag for both filling and removal of product.
These advantages are discussed in detail below. Additional ones will be apparent to those skilled in the art from the following description.